In recent years, a technology has been suggested in which an injector is arranged in a fuel supply channel of a fuel cell system, and the operation state of this injector is controlled to adjust the supply pressure of a fuel gas in the fuel supply channel (e.g., see Japanese Patent Application Laid-Open No. 2005-302563). In the injector, a valve body is driven by an electromagnetic driving force in a predetermined driving period, and detached from a valve seat, whereby a gas state (a gas flow rate or a gas pressure) can be adjusted. A control device drives the valve body to control the time to jet the fuel gas or the jet time of the fuel gas.